The two men were reportedly in possession of detailed reports about weapons shipments into Iraq, including of so-called explosively formed projectiles, which were responsible for the deaths of scores of U.S. soldiers.

Other officials say that, significantly, U.S. forces haven't seen signs that Iran is providing the Taliban the so-called explosively formed penetrator devices, which insurgents in Iraq have used to damage American armored vehicles.

Use of the armor-piercing explosives - known as explosively formed penetrators, or EFPs - has dwindled sharply in recent months, said Army Lt. Gen. Thomas Metz, head of the Pentagon office created to counter roadside bombs in Iran and Afghanistan.

But another senior military official said it will include mortars, rockets, small arms, roadside bombs and armor-piercing explosives — known as explosively formed penetrators or EFPs — that troops have discovered in caches in recent months.